Find the named dance and approach
A broad ballroom compilation can cover very different dances and teaching systems. Read the chapter names and the course description. Record the system or syllabus if the provider names one; do not assume figures with familiar names are interchangeable.
Look for both perspectives
A partner demonstration should help you understand which role is being explained. Check whether the instruction includes separate views, spoken cues and a clear statement of the intended level. Keep questions about connection and positioning for a teacher who can observe you.
Keep history in its own context
Historical ballroom manuals are interesting records of their time. Their terminology, social assumptions and dance descriptions need context. The Library of Congress collection offers a useful starting point for reading those sources rather than treating an old diagram as a modern lesson.